This invention relates to a wrapping transmission.
A wrapping transmission, comprising a driving pulley and a driven pulley engaging with a transmission belt, transmits a power from the driving pulley to the driven pulley by use of a frictional force generated between the belt and the pulleys. For the purpose of effective transmission of this power, efforts have been made to increase the friction factor of the belt or the tension of the belt by means of tension pulleys, thereby obtaining an increased frictional force between the belt and the pulleys. An increase of the friction factor of the belt results in excessive contact of the belt with the pulleys, during belt drive, so that the belt is gradually worn away, reducing the belt life. The residual powder produced by this friction between the belt and pulleys adheres to the surface of the belt, forming a rough surface on the belt which causes a noise in the belt drive. An increase of the belt tension by using a tension pulley results in an excessive expansion of the belt, which also causes a reduction of belt life.